User:Quake1234/2025 Brynmawr earthquake

On 12 February 2025, at 01:26 UTC, a 6.6 (6.5) earthquake struck Blaenau Gwent, located in Wales, a country in the United Kingdom. The earthquake was the strongest ever recorded in British Isles.

Tectonic setting
On average, several hundred earthquakes are detected by the British Geological Survey each year, but almost all are far too faint to be felt by humans. Those that are felt generally cause very little damage. Nonetheless, earthquakes have on occasion resulted in considerable damage, most notably in 1580 and 1884; Musson (2003) reports that there have been ten documented fatalities – six caused by falling masonry and four by building collapse. The causes of earthquakes in the UK are unclear, but may include "regional compression caused by motion of the Earth’s tectonic plates, and uplift resulting from the melting of the ice sheets that covered many parts of Britain thousands of years ago."

Earthquake
According to the USGS, the earthquake had a moment magnitude of 6.5, at a depth of 10.1 km. The BGS estimated a magnitude of 6.6. It is considered one of the most unique and rare earthquakes to occur modern times.

Intensity
The earthquake was felt across all of Wales, England, Northern Ireland and Scotland. A maximum Mercalli Intensity of X (Extreme) was estimated in Brynmawr, based on the complete destruction of the town. MMI IX (Violent) shaking was recorded in towns such as Ebbw Vale, Merthyr Tydfil, Beaufort and Tredegar. Intensity VIII (Severe) was recorded in Newport, Mountain Ash, Cwmbran, Blackwood and Pontypool, while MMI VII (Very Strong) was estimated in Cardiff and Caerphilly. In England, the strongest shaking (MMI VI) was recorded in Bristol, Weston-super-Mare, Clevedon, Chepstow, Monmouth and Hereford. Shaking measuring IV (Light) was recorded in most of England's largest cities, such as Birmingham and London.

In the Republic of Ireland, shaking was felt across the entire country; a maximum Mercalli intensity of IV (Light) was estimated the southeastern coast of the country, with intensity III (Weak) recorded in Dublin. Shaking was also felt in northwestern France, including the capital Paris, the Netherlands, Belgium and Denmark. The earthquake was considered by some to be one of the most widely-felt earthquakes ever recorded.

Wales
Severe damage was reported in Cardiff, where numerous buildings reportedly collapsed.

South East England
One man was injured in Oxford after trying to escape his home by jumping out of a window.

Estimations of losses
The USGS Prompt Assessment of Global Earthquakes for Response (PAGER) service estimated an 48% probability of economic losses between US$100 million and US$1 billion. There was a 47% probability of economic losses exceeding US$1 billion. The service estimated a 54% percent probability of deaths between 100-1,000; 20% probability of deaths exceeding 1,000.